test-help: improve test coverage
Adds a test for using the help option with the version option.
Extends test coverage of commands.help_ by another 2 lines.
% init
adding a
% fold in the middle of the queue
popping p3
popping p2
now at: p1
--- a/a
+++ b/a
@@ -1,1 +1,2 @@
a
+a
p1
p3
--- a/a
+++ b/a
@@ -1,1 +1,3 @@
a
+a
+b
% fold with local changes
abort: local changes found, refresh first
--- a/a
+++ b/a
@@ -1,1 +1,3 @@
a
+a
+b